SYMPTOMS OF POISONING LYMNAEA (MOLLUSCA, GASTROPODA, LYMNAEIDAE) WITH WATER MEDIUM CHROME SULFATE

Abstract

Problem. Cr (III) ions are dangerously toxic for the hydrobionts of water system of the Dnieper River basin. The ions have not been previously studied in relation to their effect on a number of pond snail species. Aim. Hence, the aim of this work is to determine the range of concentrations of Cr (III) in aquatic environment that cause each of the subsequent phases of pathological process in pond snails: poisoning by the aforementioned toxicant, and presence of the complexes of symptoms of the pathological or adaptive nature that are typical for each phase. Methods.The study was conducted in 2018 in the laboratory of zoology of invertebrates of Zhytomyr Ivan Franko State University on 344 individuals of pond snails of the species Lymnaea atra, L. callomphala and L. turricula. The toxicological experiment was performed according to the technique of V. A. Alekseyev, the rate of heartbeat by D. A. Vyskushenko, the rate of branchial respiration by V. I. Zhadin, the mean daily food intake by A. P. Sushkina, the trematode (Trematoda) infection rates and morphological examination by T. A. Ginetsinskaya. Main results. Cr (III) ions are water-soluble endogenic, highly poisonous toxicant, which locally affects the respiratory branchial epithelium and skin epithelium of pond snails. The depression, and later the termination of aerobic respiration lead to their death from asphyxia. The course of poisoning is five-phase. At 0.5 MPC Cr (III) all vital functions of pond snails are carried out at the normal level (indifference phase). At concentrations of 1-2 MPC, Cr (III) ions cause an increase in their heart rate, intensity of branchial respiration, nutrition and digestion, locomotion (muscle) activity (stimulation phase). At 3 MPC of Cr (III) ions, the depression phase of intoxication develops, with the complex of symptoms including bradycardia, a sharp weakening of respiratory and trophic functions and muscle activity, with increasing degrees of hydremia, pastosity, necrosis of the respiratory epithelium and underlying tissues, and the occurrence of bleeding and hemorrhage (depressive, sublethal and lethal phases). Conclusions. The studied species of pond snails are highly sensitive to the action of Cr (III) ions and can be suggested for use as test objects in the system of hydroecological monitoring of terrestrial waters of Ukraine.